The invention relates to a mixing kneader for the mechanical and/or thermal treatment of products in liquid, pasty and/or pulverulent state.
Such a mixing kneader is known for example from German patent specification No. 2,349,106. There, the fixed kneading counter-element also essentially comprises a hook, which cleans off both the disk segments and the shaft. In this case, in particular the arm cleaning off the shaft is directed against the direction of rotation of the shaft. This has the disadvantage that this part of the hook, the most remote from the fastening point, is exposed to considerable forces, which may emanate for example from a very hard product encrustation on the shaft.
In an extreme case, this arm close to the shaft cuts into the product encrustation and may be torn off as the shaft continues to rotate.
Furthermore, a kneading gap through which the product is pressed forms between the arm close to the shaft and the leg close to the housing, in particular whenever the hook is of a C-shaped design. Since both the arm close to the shaft and leg the close to the housing are static parts, there may easily form between these a product bridge, which may grow until it reaches the opposite kneading element and thus build up a product torus. This has the effect of significantly worsening the kneading action.
Since the kneading counter-elements according to German Patent Specification No. 2,349,106 are exposed to considerable forces, they are preferably cast. This is also so in particular for reasons of their shaping, which is very complicated. Such a cast kneading hook is relatively expensive.
The inventor has set himself the object of developing a mixing kneader of the type mentioned at the beginning in which the kneading counter-elements can be produced inexpensively and are easier to shape. Furthermore, they are to be exposed to lower mechanical forces and, in particular, reduce the torque taken up by the shaft.